The present invention relates to a work roll crossing mill in which a pair of work rolls are inclined in respective horizontal planes with respect to associated back-up rolls and also crossed each other, and more particularly to a hot or cold tandem mill system including such work roll crossing mills.
In a conventional tandem mill system, rolling mills arranged along a rolling line have usually been all constituted by 4-high mills. Therefore, the strip crown (transverse thickness distribution) and the shape (flatness) of a strip to be rolled have been controlled by roll bending apparatus of the 4-high mills. However, because the use of only roll bending has limitations in a capability of controlling the strip crown and shape, there have recently been developed tandem mill systems equipped with various high-performance rolling mills. JP, B, 53-2140 and JP, B, 55-2121, for example, disclose a tandem mill system equipped with a rolling mill (see FIG. 3, hereinafter referred to as an HC mill) which has rolls movable in the axial direction and controls the strip crown and shape by a combination of movement of those rolls and bending of work rolls. This tandem mill system enabled control of the quarter buckle that could not be corrected until then. Also, JP, B, 59-41804 discloses a tandem mill system comprised of only those rolling mills in which rolls are crossed each other in respective horizontal planes to control the strip crown and so forth.
As a mill which comprises a 4-high mill capable of using large-diameter work rolls and has a high capability of strip crown control, JP, B, 58-23161 discloses a rolling mill (see FIG. 16, hereinafter referred to as a PC mill) in which pairs of work rolls and back-up rolls, one pair being on each of the upper and lower sides, are crossed together each other in respective horizontal planes.